Question about a simplex link between two addresses

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K1BJP

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I'd like to be able to talk 440 uhf FM/DMR simplex with a friend a good 30 miles away. I think based on my location and that it looks to be obstruction free along the path we would be good.

From 2171 summerlin st Covington Kentucky 41017
To
5589 Liberty Woods Ct Liberty Twp, Ohio 45011 USA

One design I saw that looked great was two (or more) 70cm copper loops in an array. They looked really cool and we're quite small considering the gain the managed
Think I saw them in a back issue of the arrl magazine.

Thanks for any help or suggestions!

K1BJP
 

SCPD

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Are you using a hand held at 5 watts or a base station with more power? Also height of antenna. these 2 things make or break what you are wanting to do 73 de BOB
 

N4GIX

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The most essential factor will be the "radio horizon" which is only slightly more than the absolute "line of sight" distance.

For example, to cover 30 miles reliably, the very minimum height of the antenna at each end would be 110', which calculates to ~15 miles each for a total "radio horizon" of roughly 30 miles.

Or, if one end's antenna is at 320', the other antenna need only be 40' high for 34 miles RH.

See: Radio Line of Sight Calculator for use on VHF/UHF Ham Bands
 

mmckenna

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Using some of the tools on google earth, you can do a simple/poor mans link calculator.

I put in those two addresses and set up a path between them. While one of the locations is up on a hill, there's still a number of obstructions in the straight line path between the two.
Since UHF really likes to be line of sight, and you don't have one, it would be hard to tell you this is going to work.
Throwing RF power isn't going to magically melt the hills away, same with adding antenna gain.

Fundamental issue is that there is too much dirt between the two addresses.

The way around this is to increase antenna height. That gets expensive and annoys the neighbors, so proceeding down that path should be carefully thought out first.

Other ways around this are:
Use a repeater.
Use a different band.
One of you needs to move.
 
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